Cathode ray tube with low dynamic correction voltage

A cathode ray tube provided with at least an electron gun having an electron beam generating unit for generating a plurality of electron beams arrayed in a horizontal direction and for controlling said plurality of electron beams and a main lens unit for focusing said plurality of electron beams onto a fluorescent screen, and a deflection yoke for scanning said plurality of electron beams on said fluorescent screen, said main lens unit comprising:

• electrode members constituting a first kind of a focusing electrode group adapted to be supplied with a first focusing voltage;
• electrode members constituting a second kind of a focusing electrode group adapted to be supplied with a second focusing voltage;
• and
• an accelerating electrode disposed downstream of said first and second kind of focusing electrode groups and adapted to be supplied with an accelerating voltage;
• at least two non-axisymmetric electron lenses being formed between one electrode member of said first kind of a focusing electrode group and one electrode member of said second kind of a focusing electrode group, respectively, including
• a first non-axisymmetric electron lens for focusing said plurality of electron beams stronger in a horizontal direction than in a vertical direction, both mutually opposing surfaces of said electrode members of said first and second kind of focusing electrode groups constituting said first non-axisymmetric electron lens and being formed with openings therein having a vertical diameter larger than a horizontal diameter thereof, and
• a second non-axisymmetric electron lens being a multipole lens for focusing said plurality of electron beams stronger in one of the horizontal and vertical directions and for diverging said plurality of electron beams in another of the horizontal and vertical directions when said first focusing voltage is higher than said second focusing voltage, and for diverging said plurality of electron beams in said one of the horizontal and vertical directions and focusing said plurality of electron beams in said another of the horizontal and vertical directions when said first focusing voltage is lower than said second focusing voltage, thereby reversing a polarity of said multipole lens,
• at least one of said first and second focusing voltages being a voltage of a fixed voltage superposed with a dynamic voltage varying with a deflection amount of said plurality of electron beams;
• and
• a final main lens being formed between said accelerating electrode and one of said electrode members of said first and second kind of focusing electrode groups adjacent to said accelerating electrode for focusing said plurality of electron beams in both the horizontal and vertical directions and for focusing said plurality of electron beams stronger in the horizontal direction than in the vertical direction.

A cathode ray tube provided with an electron gun having at least an electron beam generating unit for generating a plurality of electron beams arrayed in a horizontal direction and for controlling said plurality of electron beams and a main lens unit comprising a plurality of electrodes including focus electrode for focusing said plurality of electron beams onto a fluorescent screen and an accelerating electrode, said focus electrode being disposed adjacent to said accelerating electrode which is adapted to be supplied with a highest voltage, comprising a plurality of electrode members;

• a first group of at least two of said plurality of electrode members constituting at least one first electron lens having a focusing action on said plurality of electron beams which increases in both the horizontal and vertical directions with an increasing difference between a first voltage applied on one member of said first group and a second voltage applied on another member of said first group,
• a second group of at least two of said plurality of electrode members constituting a second electron lens formed between end faces thereof other than end faces of said at least one first electron lens and being a multipole lens for focusing said plurality of electron beams in one of the horizontal and vertical directions and diverging said plurality of electron beams in another of the horizontal and vertical directions depending upon which is the higher of said first voltage which varies in synchronism with deflection of said plurality of electron beams and applied to one member of said second group and said second voltage having a fixed value and applied to another member of said second group,
• said at least one first electron lens being disposed at least between a final main lens and said second electron lens,
• said final main lens being formed between said accelerating electrode and one of said plurality of electrode members adjacent to said accelerating electrode for focusing said plurality of electron beams in both the horizontal and vertical directions and for focusing said plurality of electron beams stronger in the horizontal direction than in the vertical direction.